Regen: AWD versus RWD

Reign of Ravens

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Bumping an old thread, but wondering if anyone has any further information to answer this question. I don't need AWD but the increased acceleration from the dual-motor configuration might be nice; if braking power is increased then I'm sold.

I'm curious about something else: how does the Mach-E do with one-pedal driving and backing up? In my Leaf the brakes just don't feel responsive enough to do tight maneuvering with one pedal driving (backing up, moving forward, backing up - you know the dance). One pedal driving is activated or deactivated with a physical switch in the Leaf and I always turn it off for those times, instead preferring the usual of allowing the car to roll a bit on its own with me just controlling it through the brakes. With OPD in the Leaf I'm pretty sure I'd bump something. For slow maneuvers, does the car stop almost instantly when you let off of the accelerator? There shouldn't be a difference between RWD and AWD models here because this has more to do with how quickly the brakes come on, rather than regenerative braking, but I'm curious if there's a difference in motor count there, too.
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GT vs Premium/Select regenerative braking force would also be of interest.
 

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Bumping an old thread, but wondering if anyone has any further information to answer this question. I don't need AWD but the increased acceleration from the dual-motor configuration might be nice; if braking power is increased then I'm sold.

I'm curious about something else: how does the Mach-E do with one-pedal driving and backing up? In my Leaf the brakes just don't feel responsive enough to do tight maneuvering with one pedal driving (backing up, moving forward, backing up - you know the dance). One pedal driving is activated or deactivated with a physical switch in the Leaf and I always turn it off for those times, instead preferring the usual of allowing the car to roll a bit on its own with me just controlling it through the brakes. With OPD in the Leaf I'm pretty sure I'd bump something. For slow maneuvers, does the car stop almost instantly when you let off of the accelerator? There shouldn't be a difference between RWD and AWD models here because this has more to do with how quickly the brakes come on, rather than regenerative braking, but I'm curious if there's a difference in motor count there, too.
Not sure about 1PD because I don't use it. But when I was trying it out, the braking in reverse was sudden and jerky compared to going forward.

I believe all the regenerative braking is harnessed by the rear motor. I suspect this based on tire wear over 19,500 miles and the fact that I have never felt the front motor regen. In FWD BEVs, it is very noticeable at times.
 

phidauex

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Bumping an old thread, but wondering if anyone has any further information to answer this question. I don't need AWD but the increased acceleration from the dual-motor configuration might be nice; if braking power is increased then I'm sold.
I believe all the regenerative braking is harnessed by the rear motor. I suspect this based on tire wear over 19,500 miles and the fact that I have never felt the front motor regen. In FWD BEVs, it is very noticeable at times.
I've been measuring the regen on my Premium AWD ER, and while driving is almost exclusively on the rear motor (front comes in when the pedal position is further down (you are gunning it), or when traction control is called for), regen is split very evenly between the two, and sometimes is even biased to the front.

https://www.macheforum.com/site/threads/driving-dynamics-and-charging-data-files.8473/post-246236

In that post, you can see I do a full power pull up to 60mph, then let off the accelerator (in Unbridled 1PD) - during acceleration the rear is doing most of the work, but during regen I'm getting about 50kW of regen from each motor.

On my longer drives, one thing that shows up is that during long descents the front motor handles a lot of the regen, and thus heats up faster.

As for how it feels, I use 1PD in both drive and reverse, but yes, it is a touch jerky in reverse. It could be a bit smoother, but it doesn't prevent me from parking accurately (I have to park about 6" from my garage door).
 

photoflow

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This is a great discussion, since I’m currently a Chevy Bolt owner but about to pull the trigger on a Mach-E Premium, but still deciding about AWD or RWD. I don’t need AWD per se, so it’s purely a decision based on car performance. My Chevy Bolt has great regen feel and I usually drive one pedal, so this is a very pertinent discussion about quality of regen in the AWD vs RWD. Any other opinions about regen or anything else that’s good to know about the AWD or RWD models that could help me make a decision? Thanks!
 


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I've been measuring the regen on my Premium AWD ER, and while driving is almost exclusively on the rear motor (front comes in when the pedal position is further down (you are gunning it), or when traction control is called for), regen is split very evenly between the two, and sometimes is even biased to the front.

https://www.macheforum.com/site/threads/driving-dynamics-and-charging-data-files.8473/post-246236

In that post, you can see I do a full power pull up to 60mph, then let off the accelerator (in Unbridled 1PD) - during acceleration the rear is doing most of the work, but during regen I'm getting about 50kW of regen from each motor.

On my longer drives, one thing that shows up is that during long descents the front motor handles a lot of the regen, and thus heats up faster.

As for how it feels, I use 1PD in both drive and reverse, but yes, it is a touch jerky in reverse. It could be a bit smoother, but it doesn't prevent me from parking accurately (I have to park about 6" from my garage door).
I came across this in the work shop manual and confirms what you have observed. Regen occurs on front and rear drive motors. (see below)


Secondary Electric Drive

The Secondary Electric Drive system is optional for customers who desire AWD capability and increased performance. The secondary Electric Drive powers the front wheels, and is not mechanically connected to the Primary Electric Drive system that powers the rear wheels. The Secondary ISC (S-ISC) receives its commands from the Primary Drive’s Inverter System Controller (ISC), and can operate in two basic modes:

  • Torque Control Mode – The S-ISC will receive a torque command from the ISC to help propel or brake the vehicle. Regenerative braking is split between the two axles to optimize vehicle efficiency and vehicle stability. Acceleration torque is likewise split between the Front (Secondary) and Rear (Primary) axles to maximize efficiency, performance, and handling.
  • Speed Control Mode – The S-ISC can receive a speed control command from the PCM and ISC in certain wheel slip events to maintain vehicle stability and maximize vehicle handling on slippery road surfaces. The S-ISC in all cases is under the direction and control of the ISC.
The S-ISC follows the ISC for all vehicle powerup and powerdown procedures. It conducts its own safety and functional checks during every system powerup, and assists with HV electrical discharge during every system power-down.

If either the S-ISC or the ISC are faulted, the remaining ISC will be used to drive the vehicle with reduced performance.
 
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phidauex

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If either the S-ISC or the ISC are faulted, the remaining ISC will be used to drive the vehicle with reduced performance.
Thanks for the confirmation! This bit is a nice touch - I had someone ask me if the car could drive on only one motor if the other had a problem. I wasn’t sure what to say but thought it was unlikely. This is better news.
 

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Thanks for the confirmation! This bit is a nice touch - I had someone ask me if the car could drive on only one motor if the other had a problem. I wasn’t sure what to say but thought it was unlikely. This is better news.
Yes. I thought that was interesting too. However, it appears the car first goes into a total shutdown scenario first. Then after the modules power down the system resets and the next power up cycle it uses just the one remaining good drive unit.

So, a scary adventure followed by the car actually being capable of getting you home or to the dealership. AWD does have some benefits apparently......
I hope many of us here never have a need for that feature though.
 
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photoflow

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This is all great information. I also hope we would never need to use AWD for that reason. My original inquiry purely pertained to the question if regen was better or the same with RWD or AWD. I love one pedal driving in the FWD Bolt, so I would hope the Mach-E is just as good with one pedal.
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